Chevrolet OEM VIN#

[IndyJimW]

There are several places that you may find a part of the original VIN# from Chevrolet. One place in on the engine block behind the alternator in front of the passenger head, mine was blank here.  I found mine on the rear of the transmission case on the drivers side. It will only be the last 8 digits, but the first 9 digits are company info and easy to figure out.

My Avanti VIN # 12AAV1230H1000108

My Chevrolet VIN # 1G1GZ11G7HR102501

Also when I purchased my Avanti from out of state, the State Police had to verify my VIN etc. In order for the Avanti to come up in their system we had to change the 9th digit from a 0 to a 3.

Good luck,

Jim Wood

Edited December 27, 2020 by IndyJimW

[JensenHealey]

I jacked my 1989 convertible up and carefully looked around underneath at the transmission and I was not able to find any indication of any sort of number on the transmission case. Isn't there any place on the actual frame of the car where something is also stamped?

Any chance of posting a photo of where this number on the transmission case is supposed to be found?

[Randy Atkin]

Some very inexpensive OBD code readers like the Autel model MS309 will display the vehicles original VIN number. This is how I was able to determine the Ford VIN on my 06 Avanti. What I am not sure of is if the 87-88 Monte Carlo has the type of computer that accepts an OBD scanner. You might want to look near the bottom of the dash on drivers side to see if it has the multi pin female receptacle for the scanner.

[JensenHealey]

I think 1989 is long before ODB1 so I will check for the ODB1 receptical on my 1989 convertible with TBI fuel injection but I have my doubts that it is available on these cars. 
Since the 1988 cars are carbureted I am 100% positive those have no self diagnostic ports on them at all.

Also I am not sure but I don't think this sort of info is accessible at all in a OBD1 system.

Edited December 27, 2020 by JensenHealey

[IndyJimW]

If you have a check engine light on the dash you will have an ECM and a connector.

1987 thru 1991 Avanti will have an OBDI connector located on the drivers side below the dash.

WARNING: This will be the older OBDI not the newer OBDII.

Most code readers will only show you codes and not data.

I don't believe you will get vehicle info from these older ECMs. I know I recently changed out my ECM because of a driveability problem last month and you don't have to program them. Plug and Play. I have also replaced the ECM prom chip. Plug and Play also.

OEM VIN# will greatly help with engine and emission parts ordering or performance upgrades.

Same with suspension, steering, brakes and drive train.

Here is more info on finding your Chevrolet VIN#

https://www.montecarloss.com/VIN.html

Good luck,

Jim Wood

[IndyJimW]

23 hours ago, JensenHealey said:

I think 1989 is long before ODB1 so I will check for the ODB1 receptical on my 1989 convertible with TBI fuel injection but I have my doubts that it is available on these cars. 
Since the 1988 cars are carbureted I am 100% positive those have no self diagnostic ports on them at all.

Also I am not sure but I don't think this sort of info is accessible at all in a OBD1 system.

OBDI started on Chevrolets in the early 1980's. My 1987 Avanti Coupe is based on the Monte Carlo which came will a CCC type carburetor. CCC stands for Computer Controlled Carburetor. It has an ECM and OBDI connector. It also has an O2 sensor.

Your TBI system will also have an OBDI connector, although I am not sure Avanti Corp. placed it in the correct area. I can't recall but mine may have been behind the center console or on the passenger side, BUT there is one.

Good luck,

Jim Wood

 

 

Edited December 28, 2020 by IndyJimW